1. Field of the Invention
The present invention relates to a wiring harness arrangement assembly for transmission of a power and signals between a car body side and electrical equipment including auxiliary instruments disposed in a sliding door side. Particularly, the wiring harness is covered by a corrugated tube, and the wiring harness arrangement assembly has a pivotal harness guide to allow a sufficient flexibility and an appropriate torsional performance of the wiring harness received in the corrugated tube.
2. Related Art
A one-box car or a wagon has a sliding door for which various types of electric supply units have been proposed to supply a power from a power source disposed in a car body side to the sliding door and to transmit electrical signals from the sliding door to the car body side.
The sliding door is equipped with several types of functional instruments such as electrical equipment and auxiliary instruments like a motor for opening and closing a window, a door lock unit, a speaker, a switch unit, and an electronic control unit. For the functional instruments, it is necessary to supply an electrical power and to transmit electrical signals not only when the sliding door is closed but also the sliding door is open.
FIGS. 11A and 11B show an example of a conventional wiring harness arrangement assembly for a sliding door.
The wiring harness, which is received in an annular corrugated tube 4, is arranged from a car body 1 to a sliding door 6. The corrugated tube 4 is made of a synthetic resin material and has an inner diameter larger than a wiring harness (not shown). The corrugated tube 4 is a bellows constituted by a thin shell having a rectangular cross-section so that the corrugated tube 4 is flexible together with the wiring harness.
FIG. 11A shows a closed state of the sliding door 6. As illustrated in the drawing, a longitudinal middle portion of the corrugated tube 4 is secured on a step 2 of the car body 1 with a clamp 90. The corrugated tube 4 is curved from the clamp 90 to extend toward a rearward end of the sliding door 6. Each electrical cable of the wiring harness is connected to one of the functional instruments (not shown) in the sliding door. The wiring harness consists of a plurality of the electrical cables.
As illustrated in FIG. 11B, with the rearward sliding of the sliding door 6 along an arrow B to open the door, the wiring harness is bent rearward together with the corrugated tube 4 to absorb the sliding stroke of the sliding door 6.
However, in the conventional configuration, the opening and closing movement of the sliding door 6 causes the corrugated tube having the wiring harness to be forcedly bent with a smaller bending radius at an adjacent position 4a of the clamp 90 or at an adjacent position 4b of the rear end of the sliding door 6. Thus, repeated opening and closing operations of the sliding door 6 tend to disadvantageously cause a damage of the wiring harness and the corrugated tube 4 at the bent portions 4a and 4b. The forcible local bent with a smaller bending radius of the wiring harness and the corrugated tube 4 exerts an undesirable force on the wiring harness and the corrugated tube 4. This causes a strong reaction force of the wiring harness and the corrugated tube 4, providing an interference between the corrugated tube 4 and the sliding door 6 or the car body 1. Furthermore, the corrugated tube 4 may be possibly pinched between the sliding door 6 and the car body 1. Thereby, a damage of the wiring harness and the corrugated tube 4 may happen and an undesired noise may be generated. Moreover, a torsional force may be exerted on the wiring harness and the corrugated tube 4 due to the forcible bent of the corrugated tube 4, causing a damage of the wiring harness and the corrugated tube 4. That is, a smooth bending of the corrugated tube 4 has been disadvantageously prevented.
Furthermore, since the clamp 90 is disposed at a different position according to a type of a car or a sliding door, the adjacent positions 4a and 4b of the wiring harness and the corrugated tube 4 receive abnormal forces, and a smooth bending of the wiring harness and the corrugated tube 4 is disadvantageously prevented.
The use of a flexible flat cable (FFC) in place of a wiring harness improves a bending performance thereof. However, the flat cable is constituted by printed circuit conductors each having a small sectional area and an insulating sheet, so that the flat cable disadvantageously has a small transmission capacity for supplying a small amount of an electrical power and electrical signals.
The use of a junction switch unit for switching each of electrical cables to connect to each functional instrument results in an increase of a manufacturing cost.